I have a problem with people that think it's fine to waste other people's time, whether they're tanks doing single pulls so that they can avoid using defensive cooldowns, dps that don't aoe or healers that don't use oGCD heals and just spam their basic healing spell while doing close to 0 damage it makes no difference.
I have a problem with people that don't care about being an asset to their party and are completely fine with being a liability.